In particular, the present invention has application for making a seal connection between a wall of an inspection pit and a pipe intersecting it, wherein the wall of the pit passed through by the pipe is generally made from thermoweldable material, like for example plastic material and, more specifically, polyethylene.
As an example, the present invention is advantageously applicable as a penetration fitting for inspection pits of underground tanks, pits of collectors for geothermal probes, inspection pits of electric cables and/or telecommunication cables and so on, which are all characterised by the possibility of forming or by the presence, in at least one wall, of an opening for the passage of a pipe.
In such pits it is essential to make a water-tight connection between the opening and the pipe passing through in order to avoid infiltrations of liquids inside the pit.
For this purpose it is known to use special rubber coatings fixed through jubilee clips or, alternatively, mechanical fastening means equipped with rubber gaskets that are interposed between the fitting and the wall of the pit.
Such solutions do, however, have the drawback of a limited reliability over time, since rubber gaskets are subject to a lot of wear.
Moreover, it is known to make fittings provided with an annular flange with radial extension with respect to the axis of the fitting and towards the outside of the fitting, for positioning in abutment on the wall of the pit and the subsequent connection to it.
Penetration fitting provided with an annular flange differ from one another in the method of connection thereof to the wall of the pit, with it being able to be carried out through ultrasound welding, thermowelding, gluing or another type of connection through chemical agents.
Specifically, such fittings, at the annular flange, make an annular connection with the wall of the pit placed around the through opening for the pipe made in the wall of the pit, in this way insulating the opening in a sealed manner.
All of the solutions that make use of an annular flange for the creation of an annular connection concentric to the opening are not without drawbacks.
Firstly, in order to make an annular connection, the flange must have a relevant radial extension that allows to house the means for making the connection, such as an electric resistance in the case of connection through thermowelding.
It is therefore necessary to have a substantial support surface, which limits the possibilities of arranging the fitting on the wall of the pit.
In addition, even small imperfections in the abutment of the wall of the pit with the flange lead to making a weakened annular connection and, consequently, not very suitable for counteracting the fatigue stresses to which it is exposed.
All of this leads to low reliability over time of the connections made through known flange-type penetration fittings.
In order to reduce this drawback, while flange-type penetration fittings are applied it is necessary to preliminarily treat the portion of wall of the pit against which the flange will rest through the use of special manual processing tools and possibly of suitable chemical agents.
This makes the application of known penetration fittings particularly laborious and it takes a lot of man-hours.